Oligosaccharide Metabolism Research Articles

Whole-genome resequencing and transcriptional profiling association analysis revealed the intraspecies difference response to oligosaccharides utilization in Bifidobacterium animalis subsp. lactis.

As prebiotics, oligosaccharides are frequently combined with Bifidobacterium to develop synbiotic products. However, a highly diverse gene repertoire of Bifidobacterium is involved in sugar catabolism, and even phylogenetically close species may differ in their sugar utilization capabilities. To further explore the mechanism underlying the differences in Bifidobacterium animalis subsp. lactis oligosaccharide metabolism. This study screened strains with differential oligosaccharide metabolism. Subsequently, these strains were subjected to genome-wide resequencing and RT-qPCR. The resequencing results indicated that the subspecies of B. animalis subsp. lactis had a high genome similarity. The RT-qPCR results revealed that glycosidase genes exhibited consistency in the phenotype of metabolism at the transcriptional level; the better the growth of the strains on the oligosaccharides, the higher was the expression of glycosidase genes related to the oligosaccharides. Our results suggested that the differences in the gene transcription levels led to intraspecies differences in the ability of the strains to metabolize oligosaccharides even when they belonged to the same subspecies. Future studies with more sample size could generalizable the conclusion to all B. animalis subsp. lactis strains, thus would lay the theoretical foundation for the utilization of the B. animalis subsp. lactis strain as probiotics and the development of synbiotic products.

Genome-scale metabolic modeling of the human milk oligosaccharide utilization by Bifidobacterium longum subsp. infantis.

Bifidobacterium longum subsp. infantis is a representative and dominant species in the infant gut and is considered a beneficial microbe. This organism displays multiple adaptations to thrive in the infant gut, regarded as a model for human milk oligosaccharides (HMOs) utilization. These carbohydrates are abundant in breast milk and include different molecules based on lactose. They contain fucose, sialic acid, and N-acetylglucosamine. Bifidobacterium metabolism is complex, and a systems view of relevant metabolic pathways and exchange metabolites during HMO consumption is missing. To address this limitation, a refined genome-scale network reconstruction of this bacterium is presented using a previous reconstruction of B. infantis ATCC 15967 as a template. The latter was expanded based on an extensive revision of genome annotations, current literature, and transcriptomic data integration. The metabolic reconstruction (iLR578) accounted for 578 genes, 1,047 reactions, and 924 metabolites. Starting from this reconstruction, we built context-specific genome-scale metabolic models using RNA-seq data from cultures growing in lactose and three HMOs. The models revealed notable differences in HMO metabolism depending on the functional characteristics of the substrates. Particularly, fucosyl-lactose showed a divergent metabolism due to a fucose moiety. High yields of lactate and acetate were predicted under growth rate maximization in all conditions, whereas formate, ethanol, and 1,2-propanediol were substantially lower. Similar results were also obtained under near-optimal growth on each substrate when varying the empirically observed acetate-to-lactate production ratio. Model predictions displayed reasonable agreement between central carbon metabolism fluxes and expression data across all conditions. Flux coupling analysis revealed additional connections between succinate exchange and arginine and sulfate metabolism and a strong coupling between central carbon reactions and adenine metabolism. More importantly, specific networks of coupled reactions under each carbon source were derived and analyzed. Overall, the presented network reconstruction constitutes a valuable platform for probing the metabolism of this prominent infant gut bifidobacteria.IMPORTANCEThis work presents a detailed reconstruction of the metabolism of Bifidobacterium longum subsp. infantis, a prominent member of the infant gut microbiome, providing a systems view of its metabolism of human milk oligosaccharides.

Independent metabolism of oligosaccharides is the keystone of synchronous utilization of cellulose and hemicellulose in Myceliophthora.

The effective utilization of cellulose and hemicellulose, the main components of plant biomass, is a key technical obstacle that needs to be overcome for the economic viability of lignocellulosic biorefineries. Here, we firstly demonstrated that the thermophilic cellulolytic fungus Myceliophthora thermophila can simultaneously utilize cellulose and hemicellulose, as evidenced by the independent uptake and intracellular metabolism of cellodextrin and xylodextrin. When plant biomass serviced as carbon source, we detected the cellodextrin and xylodextrin both in cells and in the culture medium, as well as high enzyme activities related to extracellular oligosaccharide formation and intracellular oligosaccharide hydrolysis. Sugar consumption assay revealed that in contrast to inhibitory effect of glucose on xylose and cellodextrin/xylodextrin consumption in mixed-carbon media, cellodextrin and xylodextrin were synchronously utilized in this fungus. Transcriptomic analysis also indicated simultaneous induction of the genes involved in cellodextrin and xylodextrin metabolic pathway, suggesting carbon catabolite repression (CCR) is triggered by extracellular glucose and can be eliminated by the intracellular hydrolysis and metabolism of oligosaccharides. The xylodextrin transporter MtCDT-2 was observed to preferentially transport xylobiose and tolerate high cellobiose concentrations, which helps to bypass the inhibition of xylobiose uptake. Furthermore, the expression of cellulase and hemicellulase genes was independently induced by their corresponding inducers, which enabled this strain to synchronously utilize cellulose and hemicellulose. Taken together, the data presented herein will further elucidate the degradation of plant biomass by fungi, with implications for the development of consolidated bioprocessing-based lignocellulosic biorefinery.

Cost-effectiveness of velmanase alfa vs. bone marrow transplantation or no causal therapy in patients with mild to moderate alpha-mannosidosis

Alpha-mannosidosis is an inherited rare disorder of mannose-containing oligosaccharides metabolism that is currently treated by enzyme replacement therapy (ERT), bone marrow transplantation (BMT), or supportive therapy (ST). However, the relative cost-effectiveness of these treatment options is yet unknown. Our study aimed to compare the cost-effectiveness of the treatment options for mild to moderate alpha-mannosidosis. The study is based on a modeling approach using a Discrete-Event Simulation model to generate and simulate the course of the disease under the influence of each of the treatment options: ERT, BMT, and ST. The model had a lifetime horizon and was made from the perspective of the Serbian Health Insurance Fund. Currently, available causal therapy of mild to moderate alpha-mannosidosis with velmanase alpha enzyme replacement is not cost-effective compared with supportive therapy (ICER = 941,587,152 RSD) or bone marrow transplantation (ICER = −398,412,755 RSD). Bone marrow transplantation can be cost-effective compared to supportive therapy (ICER = 6,032,689 RSD), but only if the willingness-to-pay threshold is increased to 9 gross domestic products (GDP) per capita per QALY gained. According to the current threshold, velmanase-alfa is not cost-effective compared to BMT or ST. To make alfa-mannosidosis therapy widely accessible to patients, criteria for assessing the cost-effectiveness of orphan drugs must include not only the absolute value of ICER but other aspects like equity weightings of QALYs, risk-sharing, reimbursement of severe forms of a disease only, or availability of dedicated funding.

Identification of proteins associated with changes in oligosaccharide metabolism in Lycium barbarum L. fruit by using iTRAQ technology

Oligosaccharides are important functional active components of Lycium barbarum L. (LBL, “Goji”) fruits, but their metabolic mechanisms are not yet clear. In this study, we firstly investigated the changes in the content of oligosaccharides in LBL at different stages (S1–S5), and found that it mainly accumulated at S3 and S4. Secondly, the structural characteristics of LBL oligosaccharide (LBO) were studied by GC-MS and FT-IR. Thirdly, using iTRAQ proteomics analysis, we identified 135 differentially expressed proteins associated with oligosaccharide metabolism, which is mainly accomplished through the collaboration of a range of key enzymes. At S1 and S2, oligosaccharide synthesis was achieved mainly through photosynthesis, and changes in anabolism were mainly associated with the expression of sucrose synthase, sucrose phosphate synthase and hexokinase. Oligosaccharide accumulation was achieved through starch and polysaccharide metabolism and cellulose catabolism at S3 and S4, where the enzymes associated with changes in oligosaccharide anabolism included glycosylase, β-fructosidase and glucan endonuclease. This report will provide a theoretical basis for further elucidating the mechanisms of oligosaccharide anabolism during the growth and development of LBL.

Recent Advances on Structure, Metabolism, and Function of Human Milk Oligosaccharides and the Role in Immunity and Infant Nutrition Enforcement …!

Recent Advances on Structure, Metabolism, and Function of Human Milk Oligosaccharides and the Role in Immunity and Infant Nutrition Enforcement …!

Complex pectin metabolism by Lactobacillus and Streptococcus suggests an effective control approach for Maillard harmful products in brown fermented milk

Harmful Maillard reaction products (HMRPs) derived from brown fermented milk pose a potential threat to human health, but the conversion mechanism during the manufacturing process remains elusive and urgently needs to be controlled. Acrylamide (FC 2.14, adjusted p-value = 0.041), 5-hydroxymethylfurfural (FC 2.61, adjusted p-value = 0.026) and methylglyoxal (FC 2.07, adjusted p-value = 0.019) were identified as the significantly increased HMRPs after browning in this study and the analysis of proteomics integrated with untargeted metabolomics demonstrated that the degradation of HMRPs was jointly accomplished by Streptococcus thermophilus and Lactobacillus bulgaricus. The galactose oligosaccharide metabolism in Streptococcus thermophilus was identified as a key biochemical reaction for HMRPs degradation, and the hydrolysates of pectin could be utilized as prebiotics for Streptococcus thermophilus. Eighteen classes of enzymes of L. bulgaricus and Streptococcus thermophilus related to energy metabolism were upregulated in the pectin-added group, indicating that the entry of acrylamide and methylglyoxal into the tricarboxylic acid cycle was accelerated. NAD-aldehyde dehydrogenase and alanine dehydrogenase are enzymes belonging to Streptococcus thermophilus, and their downregulation accelerated the efflux of acetate, which was beneficial for the proliferation of L. bulgaricus and prevented the conversion of pyruvate to l-alanine, thus facilitating the energy metabolism. The recoveries and relative standard deviations of the intraday and interday precision experiments were 89.1%-112.5%, 1.3%-8.4% and 2.1%-9.4%, respectively, indicating that the developed approach was credible. Sensory evaluation results revealed that the brown fermented milk added with pectin had a better flavor, which was due to the fact that the supplement of polysaccharide promoted the fatty acid metabolism of lactic acid bacteria and increased the aroma substances including octoic acid and valeric acid. This study provided an insight into the formation and degradation mechanism of HMRPs in brown fermented milk, aiming to reduce the intake of advanced glycation end products in the diet.

Comparative transcriptome analysis of leaves of sour jujube seedlings under salt stress

Sour jujube is a tree species native to China, which has often been used as the rootstock for the propagation of other cultivars of jujube. In addition, its fruit can be used in the practice of traditional Chinese medicine. Thus, sour jujube has been regarded as a highly valuable plant scientifically and ecologically. Sour jujube is mostly planted in Northwest China and has extremely high salt tolerance. However, the molecular mechanism of its salt tolerance is yet to be fully understood. This study was carried out in the Laboratory of Agricultural College of Dalian Nationalities University. Two treatments were performed on the leaves of sour jujube seedlings with the experimental group (H3) being treated by 300 mM NaCl for 3 h, and the control group (CK) by sterile water for 3 h. A total of 47.02 GB of valid data and 32,730 annotated genes were obtained. Based on the gene expression in the comparison group, 2295 significantly differentially expressed genes (DEGs) were obtained, of which 807 and 1488 were upregulated and downregulated, respectively. According to gene function annotation and enrichment analysis, 148 genes were obtained, which are mainly involved in signal transduction of plant hormones (38), homeostasis of cell walls (27), secondary metabolism of organic matter (32), and redox reactions (20) in the leaves of sour jujube seedlings under salt stress. Among these DEGs, some stress-related transcription factors (31) were also identified. In addition, under salt stress, raffinose family oligosaccharide (RFO) metabolism in sour jujube seedlings was found to be greatly accelerated. By investigating the molecular responses of jujube seedlings under salt stress, our study provides a scientific basis for jujube cultivation in saline-alkali land, which is beneficial to further improvement of the salt tolerance of grafted jujube trees.

Preterm Infant Fecal Microbiota and Metabolite Profiles Are Modulated in a Probiotic Specific Manner.

To compare the impact of two probiotic supplements on fecal microbiota and metabolites, as well as on gut inflammation in human milk-fed preterm infants. In this single-center observational cohort study, we assessed the effects of Bifidobacterium longum subsp. infantis or Lactobacillus reuteri supplementation on the infant gut microbiota by 16S rRNA gene sequencing and fecal metabolome by 1 H nuclear magnetic resonance spectroscopy. Fecal calprotectin was measured as a marker of enteric inflammation. Aliquots of human or donor milk provided to each infant were also assessed to determine human milk oligosaccharide (HMO) content. As expected, each probiotic treatment was associated with increased proportions of the respective bacterial taxon. Fecal HMOs were significantly higher in L. reuteri fed babies despite similar HMO content in the milk consumed. Fecal metabolites associated with bifidobacteria fermentation products were significantly increased in B. infantis supplemented infants. Fecal calprotectin was lower in infants receiving B. infantis relative to L. reuteri ( P < 0.01, Wilcoxon rank-sum test) and was negatively associated with the microbial metabolite indole-3-lactate (ILA). This study demonstrates that supplementing an HMO-catabolizing Bifidobacterium probiotic results in increased microbial metabolism of milk oligosaccharides and reduced intestinal inflammation relative to a noncatabolizing Lactobacillus probiotic in human milk-fed preterm infants. In this context, Bifidobacterium may provide greater benefit in human milk-fed infants via activation of the microbiota-metabolite-immune axis.

OsPP65 Negatively Regulates Osmotic and Salt Stress Responses Through Regulating Phytohormone and Raffinose Family Oligosaccharide Metabolic Pathways in Rice

Although type 2C protein phosphatases (PP2Cs) have been demonstrated to play important roles in regulating plant development and various stress responses, their specific roles in rice abiotic stress tolerance are still largely unknown. In this study, the functions of OsPP65 in rice osmotic and salt stress tolerance were investigated. Here, we report that OsPP65 is responsive to multiple stresses and is remarkably induced by osmotic and salt stress treatments. OsPP65 was highly expressed in rice seedlings and leaves and localized in the nucleus and cytoplasm. OsPP65 knockout rice plants showed enhanced tolerance to osmotic and salt stresses. Significantly higher induction of genes involved in jasmonic acid (JA) and abscisic acid (ABA) biosynthesis or signaling, as well as higher contents of endogenous JA and ABA, were observed in the OsPP65 knockout plants compared with the wild-type plants after osmotic stress treatment. Further analysis indicated that JA and ABA function independently in osmotic stress tolerance conferred by loss of OsPP65. Moreover, metabolomics analysis revealed higher endogenous levels of galactose and galactinol but a lower content of raffinose in the OsPP65 knockout plants than in the wild-type plants after osmotic stress treatment. These results together suggest that OsPP65 negatively regulates osmotic and salt stress tolerance through regulation of the JA and ABA signaling pathways and modulation of the raffinose family oligosaccharide metabolism pathway in rice. OsPP65 is a promising target for improvement of rice stress tolerance using gene editing.

Comparative genomic analysis revealed genetic divergence between Bifidobacterium catenulatum subspecies present in infant versus adult guts

BackgroundThe two subspecies of Bifidobacterium catenulatum, B. catenulatum subsp. kashiwanohense and B. catenulatum subsp. catenulatum, are usually from the infant and adult gut, respectively. However, the genomic analysis of their functional difference and genetic divergence has been rare. Here, 16 B. catenulatum strains, including 2 newly sequenced strains, were analysed through comparative genomics.ResultsA phylogenetic tree based on 785 core genes indicated that the two subspecies of B. catenulatum were significantly separated. The comparison of genomic characteristics revealed that the two subspecies had significantly different genomic sizes (p < 0.05) but similar GC contents. The functional comparison revealed the most significant difference in genes of carbohydrate utilisation. Carbohydrate-active enzymes (CAZyme) present two clustering patterns in B. catenulatum. The B. catenulatum subsp. kashiwanohense specially including the glycoside hydrolases 95 (GH95) and carbohydrate-binding modules 51 (CBM51) families involved in the metabolism of human milk oligosaccharides (HMO) common in infants, also, the corresponding fucosylated HMO gene clusters were detected. Meanwhile, B. catenulatum subsp. catenulatum rich in GH3 may metabolise more plant-derived glycan in the adult intestine.ConclusionsThese findings provide genomic evidence of carbohydrate utilisation bias, which may be a key cause of the genetic divergence of two B. catenulatum subspecies.

Negative impacts of sea-level rise on soil microbial involvement in carbon metabolism

Sea-level rise has been threatening the terrestrial ecosystem functioning of coastal islands, of which the most important component is carbon (C) cycling. However, metagenomic and metabolomic evidence documenting salt intrusion effects on molecular biological processes of C cycling are still lacking. Here, we investigated microbial communities, metagenomic taxonomy and function, and metabolomic profiles in the marine-terrestrial transition zone of low- and high-tide, and low- and high-land areas based on distances of 0 m, 50 m, 100 m, and 200 m, respectively, to the water-land junction of Neilingding Island. Our results showed that soil salinity (EC) was the dominant driver controlling bacterial abundance and community composition and metagenomic taxonomy and function. The metabolomic profiling at the low-tide site was significantly different from that of other sites. The low-tide site had greater abundance of Proteobacteria and Bacteroidetes (1.6–3.7 fold), especially Gammaproteobacteria, but lower abundance (62–83%) of Acidobacteria and Chloroflexi, compared with other three sites. The metagenomic functional genes related to carbohydrate metabolism decreased at the low-tide site by 15.2%, including the metabolism of aminosugars, di- and oligo-saccharides, glycoside hydrolases, and monosaccharides, leading to significant decreases in 21 soil metabolites, such as monosaccharide (l-gulose), disaccharide (sucrose and turanose), and oligosaccharides (stachyose and maltotetraose). Our study demonstrates that elevated salinity due to sea-level rise may suppress C-cycling genes and their metabolites, therefore having negative impacts on microbial metabolism of organic matter.

Shotgun metagenomic sequencing revealed the prebiotic potential of a grain-based diet in mice

In the present study, we elucidated the effect of grain-based (GB) diet containing both soluble and insoluble fibers and purified ingredients-based (PIB) diet containing only insoluble fiber, namely cellulose on mice gut microbiome using whole shotgun based metagenomic sequencing. Although the fiber content in both diet types is the same (5%) the presence of soluble fiber only in the GB diet differentiates it from the PIB diet. The taxonomic analysis of sequenced reads reveals a significantly higher enrichment of probiotic Lactobacilli in the GB group as compared to the PIB group. Further, the enhancement of energy expensive cellular processes namely, cell cycle control, cell division, chromosome partitioning, and transcription is observed in the GB group which could be due to the metabolization of the soluble fiber for faster energy production. In contrast, a higher abundance of cellulolytic bacterial community namely, the members of family Lachnospiraceae and Ruminococcaceae and the metabolism functions are found in the PIB group. The PIB group shows a significant increase in host-derived oligosaccharide metabolism functions indicating that they might first target the host-derived oligosaccharides and self-stored glycogen in addition to utilising the available cellulose. In addition to the beneficial microbial community variations, both the groups also exhibited an increased abundance of opportunistic pathobionts which could be due to an overall low amount of fiber in the diet. Furthermore, backtracing analysis identified probiotic members of Lactobacillus, viz., L. crispatus ST1, L. fermentum CECT 5716, L. gasseri ATCC 33323, L. johnsonii NCC 533 and L. reuteri 100-23 in the GB group, while Bilophila wadsworthia 3_1_6, Desulfovibrio piger ATCC 29098, Clostridium symbiosum WAL-14163, and Ruminococcaceae bacterium D16 in the PIB group. These data suggest that Lactobacilli, a probiotic community of microorganisms, are the predominant functional contributors in the gut of GB diet-fed mice, whereas pathobionts too coexisted with commensals in the gut microbiome of the PIB group. Thus at 5% fiber, GB modifies the gut microbial ecology more effectively than PIB and the inclusion of soluble fiber in the GB diet may be one of the primary factors responsible for this impact.

How far is it from infant formula to human milk? A look at the human milk oligosaccharides

Human milk is the gold standard for the nutrition of infants. Human milk oligosaccharides (HMOs) are structurally diverse sugars highly abundant in human milk but not present in infant formula. The interest in HMOs has gradually increased in recent years due to their beneficial functions on infants. Here we summarize the structures and composition of HMOs, and compare the differences of oligosaccharides in human and other mammals. The absorption and metabolism of HMOs are discussed. Then we discuss existing studies on the functional biology of HMOs. Additionally, the structure-function relationships of HMOs are presented. Finally, this review summarizes the oligosaccharides in recent infant formula as well as limitations and future perspectives of HMOs research. The structures and composition of HMOs are affected by many factors. Large amounts of HMOs are metabolized by gut microbiota, and few are absorbed into circulation to perform physiological functions. Evidences from in vitro and in vivo studies, as well as clinical trials suggest that HMOs modulate gut microbiota, reduce pathogen adhesion, modulate epithelial cell and immune responses, reduce the risk of necrotizing enterocolitis and promote brain development and cognition. The specific structure determines different functions. Currently two HMOs, 2′-fucosyllactose and Lacto- N -Neotetraose, have been demonstrated safe and well-tolerated to be added into infant formula. However, the application in HMOs has been limited due to their insufficient availability. Thus, basic and clinical studies of HMOs need to be further elucidated. • The structures and composition of human milk oligosaccharides are summarized. • The absorption and metabolism of human milk oligosaccharides are discussed. • The biological functions of human milk oligosaccharides are reviewed. • The structure-function relationships of human milk oligosaccharides are presented. • The limitations and future perspectives of HMOs research are outlined.

Фактори впливу на виразність клініко-лабораторних проявів синдрому мальабсорбції вуглеводів у дітей раннього віку з ротавірусною інфекцією

Purpose — to determine the role of the lactase gene MCM6 allelic polymorphism 13910 C/T and the concomitant food allergy (FA) and atopic dermatitis (AD) on the formation of carbohydrate malabsorption syndrome manifestations in early-aged children with rotavirus infection (RVI). Materials and methods. 60 children aged 1–24 months with RVI were examined. The determination of single nucleotide polymorphism 13910 C/T of the MCM6 gene was performed by real-time polymerase chain reaction and the content of total Ig E in serum was determined by enzyme immunoassay for all children on the day of hospitalization. Total amount of carbohydrates in feces (Benedict's test) and the level of lactose in feces (Malfatti's test) were also determined in the dynamics of the disease (on the 3rd, 5th, 7th, 10th day). The analysis of the carbohydrate malabsorption syndrome clinical and laboratory signs was carried out in subgroups depending on the genotype 13910 C/T of the MCM6 gene and concomitant allergic pathology. Results. No significant differences were found in the maximum daily frequency of diarrhea, its duration and the frequency of intestinal colic and flatulence registration in children with genotypes C/C, C/T and T/T -13910 of the MCM6 gene (p&gt;0.05). There was no statistically significant difference in the total level of carbohydrates and lactose in feces at all stages of the disease (p&gt;0.05 on the 3rd, 5th, 7th, 10th). Children with concomitant FA and AD had 1.3 and 2 times higher daily frequency of liquid bowel movements during the height of the disease (p&lt;0.05 on the 5th and 7th days, respectively), 1.3 times longer diarrhea (p&lt;0.05), 1.6 and 1.8 times higher incidence of flatulence and intestinal colic (p&lt;0.05). These children had 3 and 3.3 times higher Benedict's test values (p&lt;0.01), as well as 3 and 2.5 times higher Malfatti's test values (p&lt;0.01; p&lt;0.05, respectively) on the 3rd and 5th days of RVI, respectively, than in patients without allergies, with a gradual decrease in this difference during the period of convalescence (p&gt;0.05 on the 10th day). Conclusions. The allelic polymorphism 13910 C/T of the MCM6 gene does not affect the degree of oligosaccharide metabolism disorders in the intestines in early-aged children with RVI. Against the background of concomitant food allergy and atopic dermatitis in children with RVI, there are more pronounced laboratory signs of carbohydrate malabsorption, and, as a consequence, diarrhea more pronounced during the height of the disease with a higher incidence of flatulence and intestinal colic. The research was carried out in accordance with the principles of the Helsinki declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the author. Key words: rotavirus infection, early-aged children, carbohydrate malabsorption syndrome, lactase gene polymorphism, food allergy, atopic dermatitis.

Transcriptome analysis reveals important candidate gene families related to oligosaccharides biosynthesis in Morindaofficinalis

Morinda officinalis How (MO) is one of the best-known traditional herbs and is widely cultivated in subtropical and tropical areas for many years, especially in southern China. Oligosaccharides are the major constituents in the roots of MO, which is well known for its therapeutic effects with anti-depression, anti-osteoporosis, memory-enhancing, ect. To date, the main gene families that regulate the biosynthetic pathway of MO oligosaccharides metabolism yet have been published. In our study, six cDNA libraries generated from six plants of MO were sequenced utilizing an Illumina HiSeq 4000 platform. Corresponding totals of more than 132.60 million clean reads were obtained from the six libraries and assembled into 25,812 unigenes with an average length of 1288 bp. Moreover, 6036 unigenes were found to be allocated to 26 pathways maps using several public databases, and 2538 differential expression genes (DEGs) were screened. Among them, 25 genes from three families were selected as the mainly candidate genes related to MO oligosaccharides biosynthesis. Then, the expression patterns of six DEGs closely related to MO oligosaccharides biosynthesis were verified by quantitative real-time PCR (qRT-PCR). Besides, the MO was clustered more closely to Coffea arabica of Rubiaceae. In summary, the transcriptomic analysis was used to investigate the differences in expression genes of oligosaccharides biosynthesis, with the notable outcome that several key gene families were closely linked to oligosaccharides biosynthesis.

Production of Organic Acid and Short-Chain Fatty Acids (SCFA) from Lactic Acid Bacteria Isolate on Oligosaccharide Media

The growth of microorganisms in food, one of which is lactic acid bacteria (LAB), can produce metabolites beneficial to health. It is essential to study the results of LAB metabolism to improve the quality of a functional food product. This study aimed to evaluate the isolates Lactobacillus acidophilus FNCC 0051 and Lactobacillus rhamnosus R23 to metabolize oligosaccharides as a carbon source so that the final fermentation product can benefit health especially in lowering cholesterol. In vitro testing was carried out on MRS media with or without oligosaccharides, either singly or in a combination consisting of galactooligosaccharides (GOS), fructooligosaccharides (FOS), inulin (IN), inulin hydrolyzate (HI), or their combination as prebiotics by adding 0.3 % oxbile (bile salt) and inoculated with 1% v/v LAB isolate culture and incubated at 37°C for 24 hours. The results showed that the main product of oligosaccharide metabolism by L. acidophilus FNCC 0051 and L. rhamnosus R23 produced several organic acids (lactic acid), including short-chain fatty acids (SCFA) (acetic acid, propionic acid, and butyric acid). The single and combined carbon sources affected the proportion of lactic acid and acetic acid produced by L. acidophilus FNCC0051 (p&lt;0.05). However, they did not affect the proportions of propionic acid and butyric acid. While in L. rhamnosus R23 (p&lt;0.05), the presence of a single carbon source significantly affected the proportions of lactic acid, acetic acid, propionic acid, and butyric acid, while the combination of oligosaccharides affected the proportions of lactic acid and butyric acid produced. SCFA is the main product of prebiotic metabolism, but the characteristics of the acid produced have not been identified. The fermentation pattern is thought to be related to molecular weight, chain length, and oligosaccharide structure. Short-chain molecules, such as FOS generally ferment more rapidly than long-chain molecules such as inulin. The results of this study indicate that both isolates can be used as probiotics in the development of symbiotic products with the addition of oligosaccharides, which have a physiological effect in lowering cholesterol levels.

Oligosaccharide Metabolism and Lipoteichoic Acid Production in Lactobacillus gasseri and Lactobacillus paragasseri.

Lactobacillus gasseri and Lactobacillus paragasseri are human commensal lactobacilli that are candidates for probiotic application. Knowledge of their oligosaccharide metabolic properties is valuable for synbiotic application. The present study characterized oligosaccharide metabolic systems and their impact on lipoteichoic acid (LTA) production in the two organisms, i.e., L. gasseri JCM 1131T and L. paragasseri JCM 11657. The two strains grew well in medium with glucose but poorly in medium with raffinose, and growth rates in medium with kestose differed between the strains. Oligosaccharide metabolism markedly influenced their LTA production, and apparent molecular size of LTA in electrophoresis recovered from cells cultured with glucose and kestose differed from that from cells cultured with raffinose in the strains. On the other hand, more than 15-fold more LTA was observed in the L. gasseri cells cultured with raffinose when compared with glucose or kestose after incubation for 15 h. Transcriptome analysis identified glycoside hydrolase family 32 enzyme as a potential kestose hydrolysis enzyme in the two strains. Transcriptomic levels of multiple genes in the dlt operon, involved in D-alanine substitution of LTA, were lower in cells cultured with raffinose than in those cultured with kestose or glucose. This suggested that the different sizes of LTA observed among the carbohydrates tested were partly due to different levels of alanylation of LTA. The present study indicates that available oligosaccharide has the impact on the LTA production of the industrially important lactobacilli, which might influence their probiotic properties.

Prebiotic Efficacy of Oligosaccharides Derived from the Immunomodulatory Glycoprotein (Agp) Purified from Ajowan (Trachyspermum ammiL.)

Ajowan (Trachyspermum ammi L.) spice has proven medicinal and nutraceutical properties. A purified glycoprotein (Agp; 30.7 kDa) with established immunomodulatory properties from ajowan was hydrolyzed with trifluoroacetic acid. The resultant glycan was analyzed for prebiotic activity. The probiotic microbes, L. delbrueckii (NCDC 10), L. acidophilus (NCDC 11) and L. casei (NCDC 17) showed potential utilization of the Agp hydrolysates. α-Arabinofuranosidase and β-galactopyranosidase are the major enzymes involved in the metabolism of oligosaccharides, and the microbes produced acetate as the major metabolic end product. Two major oligosaccharides from Agp hydrolysate were purified for structural characterization (ESI-MS, GLC, and NMR spectroscopy). Agp-oligosaccharide I is composed of three units of galactose and one unit of galacturonic acid, whereas Agp-oligosaccharide II is composed of two arabinose and two galactose residues of which one of the arabinoses is acetylated. This study may have future implications for the design of novel immune boosters and prebiotic food products.

Cranberry Proanthocyanidins and Dietary Oligosaccharides Synergistically Modulate Lactobacillus plantarum Physiology.

Plant-based foods contain bioactive compounds such as polyphenols that resist digestion and potentially benefit the host through interactions with their resident microbiota. Based on previous observations, we hypothesized that the probiotic Lactobacillus plantarum interacts with cranberry polyphenols and dietary oligosaccharides to synergistically impact its physiology. In this study, L. plantarum ATCC BAA-793 was grown on dietary oligosaccharides, including cranberry xyloglucans, fructooligosaccharides, and human milk oligosaccharides, in conjunction with proanthocyanidins (PACs) extracted from cranberries. As a result, L. plantarum exhibits a differential physiological response to cranberry PACs dependent on the carbohydrate source and polyphenol fraction introduced. Of the two PAC extracts evaluated, the PAC1 fraction contains higher concentrations of PACs and increased growth regardless of the oligosaccharide, whereas PAC2 positively modulates its growth during xyloglucan metabolism. Interestingly, fructooligosaccharides (FOS) are efficiently utilized in the presence of PAC1, as this L. plantarum strain does not utilize this substrate typically. Relative to glucose, oligosaccharide metabolism increases the ratio of secreted acetic acid to lactic acid. The PAC2 fraction differentially increases this ratio during cranberry xyloglucan fermentation compared with PAC1. The global transcriptome links the expression of putative polyphenol degradation genes and networks and metabolic phenotypes.